This invention discloses a microbial self-healing bio-aggregate, belonging to the field of concrete
material technology. It is composed of microorganisms, low-alkali
cement, synergistic repair components, and nano-active fillers. The microorganisms are *Bacillus pasteurellii*, the low-alkali
cement is sulfoaluminate
cement, the synergistic repair components include
urea as a metabolic substrate and organic
calcium salts as an external
calcium source, and the nano-active fillers are nano-silica or nano-
calcium carbonate. The internal pore pH value of the low-alkali cement stone is 9.0 to 11.0. When the bio-aggregate is incorporated into concrete as a functional aggregate and cracks form along with the concrete, and water enters the cracks, the microorganisms inside the low-alkali cement stone react with the synergistic repair components under the influence of water, forming mineralized deposits at the crack locations to achieve crack repair.